Climate Change - Causes and Impacts

Question 1

What is the difference between climate and weather?

Answer 1

Climate
- describes how the atmosphere behaves over relatively long periods of time

Weather
- is the daily result of changes of temp, pressure + precipitation in our atmosphere

Question 2

Both weather and climate are affected by:

Answer 2

Clouds
- trap heat underneath them // reflect sunlight away from Earth above them

Forest fires
- release co2, but regrowth traps it again in carbon stores

Volcanic eruptions

• release huge quantities of ash, which circulate in atmosphere cooling the Earth
• Mt Pinatubo in philippines erupted in 1990 lowering global temps for a few years

Human activities

• burn fossil fuels
• keep livestock

Question 3

Factors that influence climate change:

Answer 3

• Fluctuations in solar insolation affecting temperature

- Changing proportions of gases in atmosphere released by organisms

Question 4

What is Global Warming Potential (GWP) ?

Answer 4

A relative measure of how much heat a known mass of a GHG traps over a number of years compared to the same mass of carbon dioxide

Question 5

What is the GWP of carbon dioxide compared to methane?

Answer 5

Carbon dioxide has a GWP of 1
Methane has a GWP of 21

So methane traps 21 times as much heat as the same mass of carbon dioxide

Question 6

Cattle as a source of methane

Answer 6

• 60% of methane in the air is from humans + 15% of this is from cattle
• there are 1.3billion cattle in the world
• bacteria live in anaerobic conditions in their stomachs + break down cellulose in grass
• they release methane as waste product
• amounts to 100million tonnes methane p/a

Question 7

What are the facts of global warming that are not in debate?

Answer 7

• there is a greenhouse effect
• GHG emissions are increasing due to human activities
• there has been a recent pattern of inc. average global temp

Question 8

Why are oceans slightly acidic ?

Answer 8

• oceans absorb co2
• they are now slightly more acidic as they have absorbed half the carbon produced by anthropogenic activities, affecting coral etc…
• but as they warm, they release more co2 to the atmosphere

Question 9

Example of positive feedback in oceans

Answer 9

• huge amounts of methane frozen in methane clathrates in ocean sediments
• if these are released, volume of methane in atmosphere will increase dramatically

Question 10

Example of negative feedback in oceans

Answer 10

• oceans absorb more co2 in warmer water as phytoplankton photosynthesise faster
• producing more phytoplankton that absorb more co2 so dampening global warming

Question 11

Example of positive feedback in clouds

Answer 11

More evaporation leads to more clouds which trap more heat

Question 12

Example of negative feedback in clouds

Answer 12

More evaporation leads to more clouds which reflect more heat